I want to get a Timespan structure which represent a year in C#.
The tricky thing is that what a year is, depends on where it starts.
You can do
DateTime now = DateTime.Now;
TimeSpan span = now.AddYears(1) - now;
This would give you the 1 year timespan from the current moment to one year later
The key question here is: which year?
The length of the timespan obviously depends on whether the year you want is a leap year or not and when it starts.
If you want one year starting from today go with #sehe's answer.
If you want the current year go with #Oyvind,
If you want a reasonable approximation you can go with #Nayan, or for a 365.25 approximation use:
TimeSpan oneYearSpan = new TimeSpan(365, 6, 0, 0);
You can't, as a year doesn't have a fixed length (is it 365 or 366 days or about 365.25?). That's also why you can't have a month as TimeSpan (28, 29, 30, 31 days??)
Rough example:
TimeSpan oneYearSpan = new TimeSpan(365, 0, 0, 0);
Will this do?
DateTime intialDate = Date.Now.Date;
TimeSpan yearSpan = intialDate.AddYears(1).Subtract(intialDate)
As other peoplehave mentioned you may want to consider leap years. In that case you can intiate intialDate accordingly.
If you want to be pretty accurate you could use the number of nano seconds in a year.
I think that this moves by 0.5 seconds every century, so should be good for a long while yet!
public TimeSpan MyYear
{
get
{
// Year = 3.1556926 × 10^16 nanoseconds
return new TimeSpan(31556926000000000);
}
}
There are already some good answers on this page, this is just another option.
It depends on which year you want to represent, since not all years are of equal length.
This is the way to find the length of 2010 for example:
var timestamp = new DateTime(2011, 1, 1) - new DateTime(2010, 1, 1);
Change the year in the DateTimes to find the length of the year you want.
Here's how to do this, utilizing the IsLeapYear to determain number of day.
int span = DateTime.IsLeapYear(1996) ? 366: 365;
var year1996 = new TimeSpan(span, 0, 0, 0);
Related
For my SteamBot I want to store the date and the time when the item is tradable again.
Example:
// DateNow = 05.06.2019 13:37:00
(+ 7 days due to Steam's trade policy)
// DateNow+7Days = 12.06.2019 13:37:00
// DateIneed = 13.06.2019 09:00:00
So the DateTime I need is CurrentDateTime + 7 Days + The rest to 9 o'clock
This is how far I come:
var date = DateTime.Now.AddDays(7);
Is there any smart way to always get the DateTime I need?
Language is C#
You can check if it is before 9 o'clock today, then set the time to 9, else add one day and set the time to 9, should be fairly easy I think.
var time = DateTime.Now;
var date = time.Hour <= 9
? time.Date.AddDays(7).AddHours(9)
: time.Date.AddDays(7).AddHours(9).AddDays(1);
The DateTime.Date field exposes just the date of a DateTime, you can then add an arbitrary TimeSpan to that to set the time of a DateTime object to whatever you want;
DateTime.Now.AddDays(7).Date.Add(new TimeSpan(9, 0, 0))
Check it out in action here: https://dotnetfiddle.net/l3X37y
Given the hour of the day may be past 9AM already, it's possible to end up with a DateTime less than 7 days, to counter this you can check if the hour of the day exceeds what you're going to set the DateTime to and add a day if it does, like so;
DateTime dt = DateTime.Now.AddDays(7);
dt = dt.Date.Add(new TimeSpan(dt.Hour >= 9 ? 1 : 0, 9, 0, 0))
See this one in action here: https://dotnetfiddle.net/lfVGis
This question already has answers here:
how to calculate number of weeks given 2 dates?
(7 answers)
Closed 9 years ago.
Lets say, I have two date Order date - 1/1/2014 and Delivery date - 6/2/2014. Now if I want to calculate how much work week its taken (Order date-delivery date), how can I do it in c#.
If you want the number of worked days in a date range, you can use this:
var from = DateTime.Today.AddDays(-10);
var to = DateTime.Today;
var daysOfWeek = new DayOfWeek[] { DayOfWeek.Monday, DayOfWeek.Tuesday
, DayOfWeek.Wednesday, DayOfWeek.Friday
, DayOfWeek.Thursday };
var days = Enumerable.Range(0, 1 + to.Subtract(from).Days)
.Select((n, i) => from.AddDays(i).DayOfWeek)
.Where(n => daysOfWeek.Contains(n.DayOfWeek));
If you want the number of weeks during a date range, use this:
(int)((to - from).TotalDays/7)
(int)((DeliveryDate-OrderDate).TotalDays/7)
I am presuming by "how much workweek" you mean "how many workdays". This is not so straightforward as it depends on the culture and you need to take holidays into account.
If you rely on Mon through Fri being the work days you could use a solution similar to what was discussed in c# DateTime to Add/Subtract Working Days, counting each day from Order Date to Delivery Date for which the conditions hold.
That Q&A still leaves you with the issue of how to determine the holidays of a certain region (be warned - in Switzerland each part of the country has different holidays!).
Update: From Nagaraj's suggested link I gather that you might also refer to "weeks" as chunks (that is "how many workweeks it has taken"). If so, in turn, you will need to define how many days of a week must be taken to take the week into account...
I'm using strings and convert that to dates, because I'm not sure where you get your dates and in what form. Adjust your code accordingly.
string orderDate = #"1/1/2014";
string deliveryDate = #"6/2/2014";
// This will give you a total number of days that passed between the two dates.
double daysPassed = Convert.ToDateTime(deliveryDate).
Subtract(Convert.ToDateTime(orderDate)).TotalDays;
// Use this if you want actual weeks. This will give you a double approximate. Change to it to an integer round it off (truncate it).
double weeksPassed = daysPassed / 7;
// Use this if you want to get an approximate number of work days in those weeks (based on 5 days a week schedule).
double workDaysPassed = weeksPassed * 5;
I guess you are not interested in working days but weeks. You can use GetWeekOfYear:
http://msdn.microsoft.com/en-us/library/system.globalization.calendar.getweekofyear%28v=vs.110%29.aspx
EDIT
To respond to the comment, here some code example:
int start = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(new DateTime(2014, 1, 14), System.Globalization.CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
int end = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(new DateTime(2014, 2, 3), System.Globalization.CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
int weeks = end - start;
That should give you the weeks needed.
This question already has answers here:
C#: how do I subtract two dates?
(11 answers)
Closed 10 years ago.
i want to subtract previous date from current date. previous date may be 2 months and 15 days or 1 year 9 month and 10 days... like this etc... So please how can i write the Coding in C#. thanks a lot.
Any answer using TimeSpan will not be able to give you "2 months and 15 days" - as the length of a month changes over time.
Doing this using the base class libraries is a pain... which is one of the reasons I started the Noda Time project. Amongst its other features, it allows you to determine the Period between to dates (or dates and times, etc).
For example, let's see how long I've been on Stack Overflow:
LocalDate today = new LocalDate(2013, 2, 8);
LocalDate start = new LocalDate(2008, 9, 26);
// This defaults to using year, month, day units. You can specify alternatives.
Period period = Period.Between(start, today);
Console.WriteLine("{0} years; {1} months; {2} days",
period.Years, period.Months, period.Days);
Output:
4 years; 4 months; 13 days
Or if you actually wanted to subtract a period from a date (the question isn't very clear) you can do that too:
Period period = new PeriodBuilder { Years = 4, Months = 4, Days = 13 }.Build();
LocalDate today = new LocalDate(2013, 2, 8);
LocalDate start = today - period;
Console.WriteLine(start);
Output:
25 September 2008
Note that this doesn't give September 26th, because of the somewhat crazy nature of date/time arithmetic. If you added the period to September 26th you'd get today... but that's not the same thing. Treat this as a warning that you need to be really careful about describing what you want to achieve :)
This second side you can do with the BCL fairly easily though:
DateTime today = new DateTime(2013, 2, 8);
DateTime start = today.PlusYears(-4).PlusMonths(-4).PlusDays(-13);
There's no BCL type to represent that "years, months, days" value though.
Your question is a little confusing. Do you want to subtract one date from another date, or do you want to subtract a period of time from a date.
1. Subtract one date from another date:
DateTime previousDate = new DateTime(1990, 12, 12);
DateTime currentDate = DateTime.UtcNow;
TimeSpan difference = currentDate - previousDate;
You can then use the TimeSpan methods to get the difference in various units of time as you like.
Here's more info on TimeSpan: http://msdn.microsoft.com/en-us/library/system.timespan.aspx
2. Subtract a period of time from a date
DateTime currentDate = DateTime.UtcNow;
TimeSpan periodOfTime = new TimeSpan(12, 12, 0, 0);
DateTime newDate = currentDate - periodOfTime;
However, you'll have to calculate yourself what the length of a month is, if that's what you want.
You can use DateTime.Subtract.
Examples from article:
System.DateTime date1 = new System.DateTime(1996, 6, 3, 22, 15, 0);
System.DateTime date2 = new System.DateTime(1996, 12, 6, 13, 2, 0);
System.DateTime date3 = new System.DateTime(1996, 10, 12, 8, 42, 0);
// diff1 gets 185 days, 14 hours, and 47 minutes.
System.TimeSpan diff1 = date2.Subtract(date1);
// date4 gets 4/9/1996 5:55:00 PM.
System.DateTime date4 = date3.Subtract(diff1);
// diff2 gets 55 days 4 hours and 20 minutes.
System.TimeSpan diff2 = date2 - date3;
// date5 gets 4/9/1996 5:55:00 PM.
System.DateTime date5 = date1 - diff2;
TimeSpan timeSpan = new TimeSpan(2,2,0);
DateTime dateTime = DateTime.Now.Subtract(timeSpan);
When you subtract two date in C# you get a TimeSpan object.
You can acces different properties of it to get the actual days, hours, minutes etc. taht it represents:
DateTime a;
DateTime b;
//assign some values
TimeSpan span = a.Subtract(b);
Console.WriteLine("Days: " + span.Days);
The following should do.
TimeSpan diff = DateTime.Now - previousDate;
Would appreciate it if anyone can help me figure out to substract 2 datetime fields to get the days left difference.
This is very easy to do with C#. For comparing DateTimes, we have a class called TimeSpan. The TimeSpan structure, in this case, would be defined as the difference between your two datetimes.
Let's say that your DateTimes are called start and end.
DateTime start = new DateTime(2009, 6, 14);
DateTime end = new DateTime(2009, 12, 14);
We have established our DateTimes to June 14, 2009 and December 14, 2009.
Now, let's find the difference between the two. To do this, we create a TimeSpan:
TimeSpan difference = end - start;
With this TimeSpan object, you can express the difference in times in many different ways. However, you specifically asked for the difference in days, so here's how you can get that:
Console.WriteLine("Difference in days: " + difference.Days);
Thus, the property is called TimeSpan.Days.
Final Code
//establish DateTimes
DateTime start = new DateTime(2009, 6, 14);
DateTime end = new DateTime(2009, 12, 14);
TimeSpan difference = end - start; //create TimeSpan object
Console.WriteLine("Difference in days: " + difference.Days); //Extract days, write to Console.
For more information on using the TimeSpan structure, see this MSDN documentation (especially the C# examples).
Hope I helped!
UPDATE: Some answers have suggested taking doing subtraction in one step, such as with:
int days = (dt2 - dt1).Days;
or
int numDaysDiff = Math.Abs(date2.Subtract(date1).Days);
However, they are the same thing as in my answer, only shortened. This is because the DateTime.Subtract() method and the subtraction operator of DateTimes returns a TimeSpan, from which you can then access the amount of days. I have specifically used the longer approach in my code sample so that you clearly understand what is going on between your DateTime and TimeSpan objects and how it all works. Of course, the other approaches I just mentioned are fine, too.
UPDATE #2:
A very similar question was asked before, and it can be found here. However, the main point of that question was why the code sample (which is essentially equivalent to that of all the answers) sometimes provides an answer which is a day off. I think this is also important to this question.
As the main answer to the other question suggests, you can use this code:
int days = (int)Math.Ceiling(difference.TotalDays);
This code uses Math.Ceiling, which, according to MSDN, is:
Returns the smallest integral value
that is greater than or equal to the
specified double-precision
floating-point number.
How Do You Want to Count the Days?
Thus, we now have an issue with how you want to count the days. Do you want to count part of a day (such as .5 of a day) as:
A full day - this would use Math.Ceiling to round up TimeSpan.TotalDays, so that you're counting started days.
Part of a day - you can just return the TimeSpan.TotalDays (not rounded) as a decimal (in the double datatype)
Nothing - you can ignore that part of a day and just return the TimeSpan.Days.
Here are code samples for the above:
Counting as a full day (using Math.Ceiling() to round up):
//establish DateTimes
DateTime start = new DateTime(2009, 6, 14);
DateTime end = new DateTime(2009, 12, 14);
TimeSpan difference = end - start; //create TimeSpan object
int days = (int)Math.Ceiling(difference.TotalDays); //Extract days, counting parts of a day as a full day (rounding up).
Console.WriteLine("Difference in days: " + days); //Write to Console.
Counting as part of a day (NOT using Math.Ceiling(), instead leaving in decimal form as a part of a day):
//establish DateTimes
DateTime start = new DateTime(2009, 6, 14);
DateTime end = new DateTime(2009, 12, 14);
TimeSpan difference = end - start; //create TimeSpan object
double days = difference.TotalDays; //Extract days, counting parts of a day as a part of a day (leaving in decimal form).
Console.WriteLine("Difference in days: " + days); //Write to Console.
Counting as nothing of a day (rounding down to the number of full days):
//establish DateTimes
DateTime start = new DateTime(2009, 6, 14);
DateTime end = new DateTime(2009, 12, 14);
TimeSpan difference = end - start; //create TimeSpan object
int days = difference.TotalDays; //Extract days, counting parts of a day as nothing (rounding down).
Console.WriteLine("Difference in days: " + days); //Write to Console.
Use
TimeSpan
DateTime departure = new DateTime(2010, 6, 12, 18, 32, 0);
DateTime arrival = new DateTime(2010, 6, 13, 22, 47, 0);
TimeSpan travelTime = arrival - departure;
The easiest way out is, making use of TimeSpan().
This Subtract function will return you the difference between two dates in terms of time span. Now you can fetch fields like days, months etc. To access days you can make use of
Here is the sample code;
VB.Net code;
Dim tsTimeSpan As TimeSpan
Dim ldDate1 as Date
Dim ldDate2 as Date
'Initialize date variables here
tsTimeSpan = ldDate1 .Subtract(ldDate2)
Dim NumberOfDays as integer = tsTimeSpan.days
C#.Net code;
DateTime lDate1;
DateTime lDate2;
TimeSpan tsTimeSpan ;
int NumberOfDays;
//Initialize date variables here
tsTimeSpan = ldDate1 .Subtract(ldDate2);
NumberOfDays = tsTimeSpan.days;
DateTime dt1 = new DateTime(2009,01,01,00,00,00);
DateTime dt2 = new DateTime(2009,12,31,23,59,59);
int days = (dt2 - dt1).Days;
Number of Days Difference
These answers take the number of days as an int from the System.TimeSpan structure that is the result of subtracting two System.DateTime fields...
Quick answer - gets the number of days difference.
int numDaysDiff = date2.Subtract(date1).Days;
Alternate answer - uses Math.Abs to ensure it's not a negative number, just in case the dates might be supplied in either order.
int numDaysDiff = Math.Abs( date2.Subtract(date1).Days );
Some sample data to finish it off using System namespace:
// sample data
DateTime date1 = DateTime.Now;
DateTime date2 = DateTime.Now.AddDays(10);
MSDN References (and more sample code ):
System.TimeSpan structure
System.DateTime structure
System.Math.Abs(..) method
DateTime theDate = DateTime.Today;
int datediff = theDate.Subtract(expiryDate).Negate().Days;
if expiryDate > theDate then you get Negative value: -14
expiryDate is less than theDate then you get positive value: 14
You May obviously want this in a scenario such as
Send a Notification Email 14days before expiry
Send another notification Email 14 days after expiry
You need a difference that could be negative value
You should look at TimeSpan.
To get the exact days ignoring the time section
DateTime d1 = Convert.ToDateTime(DateTime.Now.ToShortDateString());
DateTime d2 = Convert.ToDateTime(DateTime.Now.AddDays(46).ToShortDateString());
var days = Convert.ToInt32(d2.Subtract(d1).TotalDays)
How can I get the age of someone given the date of birth in a C# datetime.
I want a precise age like 40.69 years old
This will calculate the exact age. The fractional part of the age is calculated relative to the number of days between the last and the next birthday, so it will handle leap years correctly.
The fractional part is linear across the year (and doesn't take into account the different lengths of the months), which seems to make most sense if you want to express a fractional age.
// birth date
DateTime birthDate = new DateTime(1968, 07, 14);
// get current date (don't call DateTime.Today repeatedly, as it changes)
DateTime today = DateTime.Today;
// get the last birthday
int years = today.Year - birthDate.Year;
DateTime last = birthDate.AddYears(years);
if (last > today) {
last = last.AddYears(-1);
years--;
}
// get the next birthday
DateTime next = last.AddYears(1);
// calculate the number of days between them
double yearDays = (next - last).Days;
// calcluate the number of days since last birthday
double days = (today - last).Days;
// calculate exaxt age
double exactAge = (double)years + (days / yearDays);
This would be an approximative calculation:
TimeSpan span = DateTime.Today.Subtract(birthDate);
Console.WriteLine( "Age: " + (span.TotalDays / 365.25).toString() );
BTW: see also this question on Stack Overflow: How do I calculate someone’s age in C#?
An approximite would be:
DateTime bd = new DateTime(1999, 1, 2);
TimeSpan age = DateTime.Now.Subtract(bd);
Console.WriteLine(age.TotalDays / 365.25);
The 40 years part is easy enough. But to get a truly accurate decimal point, I'm not sure how you translate the rest of the age into a decimal number. You see age is expressed in Years, Months, Days, Hours, Seconds. And the calculation isn't that easy. You have to deal with anniversary dates. Like if someone was born on January 31st, when are they 1 month old? The answer is March 1st. But in some years that is 28 days later and some years 29 days later. Here is a javascript implementation I did that tries to deal with this.
But I suppose the decimal could express the number of days since the most recent birthday anniversay divided by the number of days till the next birthday anniversary. And if you wanted to get more precise you could do it in seconds using the same principle.
But I think it is a poor representation of an age. We just don't usually represent an age like that.
And make sure your datetimes are in the same timezone for your comparisons.
You could do this:
Console.WriteLine(DateTime.Now.Date.Subtract(new DateTime(1980, 8, 1)).TotalDays / 365.25);
how much error is allowed in the fractional portion? a precise age would be
31 years, 10 days, 3 hours, etc. depending on the precision wanted.